Long-Term Debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017
Debt Instrument [Line Items]
Financing costs, net	$ (20,046)	$ (35,660)
Total debt, net	1,154,242	1,589,482
Less: Current portion of long-term debt	12,963	14,600
Long-term debt, net	1,141,279	1,574,882
Series B Term Loan
Debt Instrument [Line Items]
Debt instruments net of original issue discount	1,034,288
First Lien Credit Facility Term Loans
Debt Instrument [Line Items]
Debt instruments net of original issue discount		1,382,098
Second Lien Credit Facility Term Loans
Debt Instrument [Line Items]
Debt instruments net of original issue discount		109,294
Receivables Financing Agreement
Debt Instrument [Line Items]
Debt instruments net of original issue discount	$ 140,000	$ 133,750

Debt instrument carrying amount net of issue discount.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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